Catalytic oil cracking



Patented Aug. 14, 1 951 CATALYTIC OIL CRACKING Eugene V. Mathy andCarlJ. Helmers, Bartlesville, kla., assignors to Phillips PetroleumCompany, a corporation of Delaware No Drawing. Application November 10,1947,

.Serial No. 785,199

3 Claims. (01. 196 52) This invention relates to an improved process forthe catalytic cracking of hydrocarbon oils to produce a high yield ofhigh octane gasoline motor fuel. In another aspect it relates to aprocess for the catalytic cracking of hydrocarbon oils in which theyield of gaseous by-products is low. In another aspect it relates tosuch a process in which the amount of carbon deposition is low.

In still another aspect, it relates to an improved catalyst and a methodofpreparation of same.

In the production of gasoline motor fuel from petroleum, a small amountmay be obtained by simple fractionation. Since gasoline motor fuel isthe petroleum product in greatest demand, efforts are being constantlymade to devise methods or processes to produce this gasoline motor fuel7 800--1400 F., a good catalyst must be able to withstand exposure tohigh temperatures without serious impairment of efficiency. The processmust allow a high throughput of high-boiling point oil and return a highyield of high octane gasoline. The amount of dry gas (propane andlighter hydrocarbons) formed should be low. As carbon from the crackingbuilds up on the catalyst, the catalytic activity drops, and'thecatalyst must be taken out of service for regeneration when the activitydrops to a certain predetermined level. Therefore, it is desirable thatthe rate of carbon deposition be as low as is consistent with economicaloperation of the process. However, the carbon deposition increases withan increase in the space velocity'at' constant conversion or with anincrease in per cent conversion at constant space velocity, so anoptimum balance between these important factors must be maintained. 7

We have found that catalysts having a high order of activity forconverting high-boiling hydrocarbon oils into gasoline with'a superioroctane rating may be prepared by impregnating a solid, absorbent,catalytically active material with a mixed B203 and P205 promoter.

The principal object of our invention is to provide an improved processfor the catalytic conversion of high-boiling petroleum oils ,into highoctane gasoline motor fuels at a high yield through the use of thecatalyst comprising a major constituent selected from the groupconsisting of bauxite, fullers earth, acid treated montmorillonite clay,and the synthetically prepared alumina, silica, and silica-alumina gelssupporting a minor proportion of boric oxide and phosphorus pentoxide.

Another object of our invention is to provide a process for thecatalytic conversion of high-boiling point petroleum oils into highoctane gasoline motor fuels at a high yield and without forming anunduly high amount of dry gas.

Another object of our invention is to provide a process for thecatalytic conversion of highboiling point petroleum oils into highoctane gasoline motor fuels at a high yield and without depositing anunduly high amount of carbon.

Another object of our invention is to provide a process for thecatalytic conversion of highboiling point petroleum oils into highoctane gasoline motor fuels, in which process, the catalyst ismaintained at high activity and high efilciency for longer periods.

Another object is to provide a new and improved catalyst for theconversion of hydrocarbon oils into high octane gasoline.

Another object is to provide a method of preparing said catalyst.

Numerous other objects and advantages of our invention will be apparentto those skilled in the art upon reading the following specification andthe accompanying claims.

OPERATIONS not as economical, we prefer to employ in this.

catalyst from 0.1 to 10% by weight of boric oxide and from 0.1 to 10% byweight of phosphorus pentoxide.

In its operation, the high-boiling point 011 is substantially vaporizedin a preheater, passed into a catalytic reactor where it is contactedwith the catalyst for the desired time, and then passed tirely. Thecharge is'vaporized and superheated with as little thermal decompositionas possible to a temperature in the range of 850-1100 F. A pressure of10-300 pounds per square. inch gauge at the preheater outlet ispreferred.

The vaporized petroleum oil' ispassedfrom the preheater into thecatalytic reactor where it contacts the catalytic mass at a spacevelocityof from 01-10 liquid volumes ofpetroleum' oil per volume ofcatalytic mass per hour. The amount of conversion is partiallycontrolled by the. length of time the oil is exposedto the catalyst.However, if the velocity is low, the process is uneconomical beeausethetotal' product" will be low and the rate of carbon deposition increases:If

the initial high activity of the catalyst. It was calculated that thepromoter content was 1.05 weight per cent of P205 and 1.05 per cent ofB203.

A catalyst of bauxite containing P205 alone in the amount of 1.4 weightper cent and one containing B203 alone in the amount of 2.0 weight percent were prepared in a similar manner.

EXAMPLE II The four catalysts prepared in Example I were tested in afixed bed hydrocarbon cracking system charged with an oil having aboiling point essentially above that of gasoline. A catalyst temperatureof 10i5 R, a pressure of 85 pounds per square inch gauge, and anoperating period of 3 hours. were used. The space velocities, measuredin terms of liquid volumes of oil per volume of catalyst per hour, wereheld constant for" all tests. The results are shown in Table I. Theactivity index is the comparison of the per cent conversion obtainedwith each catalyst compared with that of the original bauxite.

Table I e Bauxite Bauxite Bauxite 20% B203 not B2O3':O1-505%.

Space Velocity -l 1. 8 1.' 8 1. 8" 1. 8 Per Cent Conversion. 51. 2 53. 952. 3 56. 5 Dry Gas, wt. per cent 12. 9 13.4 12. 8- 14.1 Birtanes, vol.per cent 6. 2 7. 4 7. 8 8. 1 Carbon, wt. per cent 1.8 2. 0 2. 8 3. 4Gasoline:

Yield, vol. per cent"..- 35. 0 36. 3' 34. 4 36. 2

ASTM Octane N0 75. 6 76. 6' 77. 2 76. 8

Bromine N o 91 96 88 81 Activity Index.. 100 105 102 110 silica-aluminagel which material has been im-- pregnated with a, minor proportion ofboron trioxide and phosphorus pentoxideas a combination promoter ma beused.

The efiluent gases: from. thecatalytic reactor are led into a separatorwhere the gasoline motor fuel, dry gas, and butanes are removed. Ifdesired, the high-boiling fraction maybe recycled through the system byintroducing it back into the preheater. The following examples serve toillus trate further the advantages of our invention.

EXAMPLE I Samples of our catalysts were prepared 'as-follows A portionof bauxitecontaining less than 3-per' cent of iron and having'a particlesize of 844' mesh was calcined at a temperature of 700-900 for a periodof about 10 hours to reducethe water content below 5 per cent.

A250 gram sampleof the calcined bauxite was soaked for 1 hour in 250 ml.or" solutioncontaining 10.1'grams of HSPO4 and 1L7 grams of I-Is'B'Os.The mass was then drained for "1 hour, air dried for 3 days, oven dried"at 482 F; for hours, and

heat-treated for"168*h0urs at1500 F.- to kill The bauxite impregnatedwith B203 and the bauxite impregnated with P205 catalyst has a higheractivity indexthan the untreated bauxite. Thecatalytic efiect of ourcatalyst is more than the combined effect produced by B203 and P205separately.

EXAMPLE III Another comparison was made using a. high grade bauxite'andthe same bauxite impregnated with 3203' and P205 in minor'amounts forcracking a virgin gas oil. The octane numbers were run on the productgasoline clear and with 1 and 3 'ml. of tetraethyl lead per'gallon ofgasoline; The operating conditions and results are" shown in Table II.

Table [I Bauxite Bauxite+B20 +PiO5 Pressure 85 Temperature, F 980 980Conversion, Vol. Per Cent I 52' 54 Gasoline:.

Yield, Vol Per'Cent' 38.3 35 7 Bromine N o 74 70 Cycle Stock, VOL- 48.045. 4 Dry- Gasfwt; PerOent; 9. 8 11.5 Tests. for tetraethyl leadresponsez. ASTM Octane-Numbers 0 ml. TEL pergal 74. 1 76:5 1 ml. TEL pergal 78. 5 80. 0 3 ml. TEL per gal 81.8 82. 7 ResearchOctane Numbers 0mlJTEL per gel H. 82.3 86.3 1 ml. TEL per'gali- 88.7 92.0 3 m1. TEL pergal= 92. 4 94.1

The higher conversion obtained by using our catalyst morethan'compen'sates for the'slightly lower gasoline yield. The superiorityof our catalyst'is clearly shownin the higher'octane rating of thegasoline produced? From the foregoing examples, it is apparent that thisprocess has many advantages. The catalytic activity is not impaired byprolonged exposure to high temperatures. When our catalyst is employed agasoline of a high octane rat ing is produced. The low rate of carbondeposition means prolonged life of the catalyst at high activity. Due tothe high catalytic activity as reflected in the high conversion ratio,our catalyst permits a higher space velocity or throughput than ispossible with the other catalysts tested. This means that morehigh-boiling point petroleum oil may be processed in less time and witha high yield of high octane gasoline motor fuel.

In the practicing of this invention it is obvious that variations in thearrangement may be made without invention. For instance, instead of thefixed-bed catalyst described in the examples, a fluidized bed may beused. This invention embraces such other obvious variations andmodifications as come within the scope thereof. This invention islimited only by the following claims.

Having fully described our invention, we claim:

1. A process for the conversion of hydrocarbon oils to produce a highoctane gasoline which comprises passing said oil at a crackingtemperature and pressure through a cracking zone containing an activecatalyst comprising bauxite supporting impregnated on'its surface .1 toweight per cent of phosphorus pentoxide and boron trioxide as such andmaintaining said hydrocarbon oil in contact with said catalyst for aperiod of time sufiicient to obtain the desired conversion thereof.

2. A process for cracking hydrocarbon oils which comprises contactingthe said hydrocarbon oil at a temperature of 800 F. to 1400 F., apressure between 10 and 300 pounds per square inch gauge, and a spacevelocity of from 0.1 to 10 volumes of liquid charge per volume ofcatalyst per hour with an active catalytic mass comprising bauxite as amajor constituent supporting impregnated thereon as such 0.1 to 10weight per cent of boron trioxide and 0,1 to 10 weight per cent ofphosphorus pentoxide.

REFERENCE S CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,109,866 Moser Mar. 1, 19382,341,363 Connolly Feb. 8, 1944 2,398,819 Cook Apr. 23, 1946 2,441,493Krug May 11, 1948 2,443,402 Schulze June 15, 1948 2,480,672 Plank Aug.30, 1949 OTHER REFERENCES Mellor, Comprehensive Treatise on Inorganicand Theoretical Chemistry, vol. 5, page 147.

Handbook of Chem. & Physics Hadgman and Lange, 16th edition, page 198.

1. A PROCESS FOR THE CONVERSION OF HYDROGEN OILS TO A PRODUCE A HIGH OCTANE GASOLINE WHICH COMPRISES PASSING SAID OIL AT A CRACKING TEMPERATURE AND PRESSURE THROUGH A CRACKING ZONE CONTAINING AN ACTIVE CATALYST COMPRISING BAUXITE SUPPORTING IMPREGNATED ON ITS SURFACE .1 TO 10 WEIGHT PER CENT OF PHOSPHORUS PENTOXIDE AND BORON TRIOXIDE AS SUCH AND MAINTAINING SAID HYDROCARBON OIL IN CONTACT WITH SAID CATALYST DESIRED CONVERSION THEREOF. 